/*******************************************************************************
 *
 * Copyright (c) 2004-2010 Oracle Corporation.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *
 *
 *******************************************************************************/ 

package hudson.util;

import hudson.Util;
import hudson.model.TaskListener;
import org.apache.tools.ant.DirectoryScanner;
import org.apache.tools.ant.types.FileSet;

import java.io.File;
import java.io.FileFilter;
import java.io.IOException;
import java.io.Serializable;

import static hudson.Util.fixEmpty;

/**
 * Visits a directory and its contents and pass them to the {@link FileVisitor}.
 *
 * A {@link DirScanner} encapsulates the logic of how it filters files in the
 * directory. It is also remotable.
 *
 * @since 1.343
 * @see FileVisitor
 */
public abstract class DirScanner implements Serializable {

    /**
     * Scans the given directory and pass files onto the given visitor.
     */
    public abstract void scan(File dir, FileVisitor visitor) throws IOException;

    /**
     * Scans everything recursively.
     */
    public static class Full extends DirScanner {

        private void scan(File f, String path, FileVisitor visitor) throws IOException {
            if (f.canRead()) {
                if (visitor.understandsSymlink()) {
                    String target = Util.resolveSymlink(f, TaskListener.NULL);
                    if (target != null) {
                        visitor.visitSymlink(f, target, path + f.getName());
                        return;
                    }
                }
                visitor.visit(f, path + f.getName());
                if (f.isDirectory()) {
                    for (File child : f.listFiles()) {
                        scan(child, path + f.getName() + '/', visitor);
                    }
                }
            }
        }

        public void scan(File dir, FileVisitor visitor) throws IOException {
            scan(dir, "", visitor);
        }
        private static final long serialVersionUID = 1L;
    }

    /**
     * Scans by filtering things out from {@link FileFilter}
     */
    public static class Filter extends Full {

        private final FileFilter filter;

        public Filter(FileFilter filter) {
            this.filter = filter;
        }

        @Override
        public void scan(File dir, FileVisitor visitor) throws IOException {
            super.scan(dir, visitor.with(filter));
        }
        private static final long serialVersionUID = 1L;
    }

    /**
     * Scans by using Ant GLOB syntax.
     */
    public static class Glob extends DirScanner {

        private final String includes, excludes;

        public Glob(String includes, String excludes) {
            this.includes = includes;
            this.excludes = excludes;
        }

        public void scan(File dir, FileVisitor visitor) throws IOException {
            if (fixEmpty(includes) == null && excludes == null) {
                // optimization
                new Full().scan(dir, visitor);
                return;
            }

            FileSet fs = Util.createFileSet(dir, includes, excludes);

            if (dir.exists()) {
                DirectoryScanner ds = fs.getDirectoryScanner(new org.apache.tools.ant.Project());
                for (String f : ds.getIncludedFiles()) {
                    File file = new File(dir, f);
                    visitor.visit(file, f);
                }
            }
        }
        private static final long serialVersionUID = 1L;
    }
    private static final long serialVersionUID = 1L;
}